Vehicle control apparatus and vehicle control method

ABSTRACT

Control determines whether or not two objects represent the same object, in which one object is detected at a first position in front of a vehicle by an electromagnetic wave sensor and the other object is detected at a second position in front of the vehicle by image sensor. The control further determines whether or not the other object is partially excluded from an image acquired by the image sensor, in which a part of the object may have been outside the imaging region of the image sensor. The control changes a determination condition used for determining whether or not the objects represent the same object, such that the object whose part is excluded from the acquired image is more easily determined as the same object, compared with an object determined that such a part is not excluded from the acquired image.

CROSS REFERENCE TO RELATED APPLICATION

The present application is based on Japanese Patent Application No.2016-205051 filed Oct. 19, 2016, the description of which isincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a vehicle control apparatus and avehicle control method which are for detecting an object by using acombination of an electromagnetic wave sensor and an image sensor.

BACKGROUND ART

Conventionally, there has been known a vehicle control apparatus whichuses both an electromagnetic wave sensor and an image sensor and isdesigned for detecting objects which are present in front of a vehicleprovided with the apparatus.

Practically, the electromagnetic wave sensor detects positions ofobjects and the image sensor acquires an image to detect positions ofobjects. These positions are used in a determination condition todetermine whether or not objects sensed by the respective sensorsrepresent the same.

In PTL 1, there is disclosed an apparatus in which a mutual proximity ofpositions of objects respectively detected by the electromagnetic wavesensor and the acquired image, is set as a determination condition todetermine whether or not the detected objects represent the same object.

Further, in the apparatus disclosed in PTL 1, in addition to theabove-described determination condition, there is another determinationcondition to determine whether or not objects represent the same object.This determination condition is based on a difference between twoperiods of time and a predetermined threshold. One period of time isestimated as being required for the vehicle, which is calculated basedon a current position of an object detected by the electromagnetic wavesensor, will collide with an object. The other period of time isestimated as being required for the vehicle, which is calculated basedon current position detected from acquired images, will collide with anobject. If a difference between both periods of time is equal to or lessthan the threshold, it is determined that both objects represent thesame object.

CITATION LIST Patent Literature Patent Literature

JP 2016-66182 A

SUMMARY

Incidentally, when calculating the position of an object using theacquired images, a known pattern matching process can be used forrecognizing an object, for example.

Since the pattern matching process can recognize an object even when thewhole image of an object is not included in the acquired images, theobject may be recognized only when a part of the object is outside theimages.

As a result, an object recognized in the state of being partiallyexcluded from the acquired images tends to deviate when being comparedto the object with its whole image being recognized in the acquiredimages. This causes a deviation in the calculated position in theimages.

Due to this deviation, two objects which are highly likely to representthe same object may be erroneously determined as different objects inthe determination process for determining whether or not they representthe same object.

The present disclosure has been made in view of the above describedproblems, and a purpose thereof is to provide a vehicle controlapparatus and a vehicle control method, which are for detecting anobject by using both an electromagnetic wave sensor and an image sensor,and which is possible to minimize a decrease in determination accuracyas to whether or not the detected objects represent the same object.

The present disclosure relates to a vehicle control apparatus includingan object determination unit that determines whether or not objectsrepresent a same object based on a first position at which an objectwhich exists in a field in front of a own vehicle is detected by anelectromagnetic wave sensor and a second position of an object detectedfrom an image of a forward view of the own vehicle, the image beingacquired by an image sensor.

The vehicle control apparatus further includes: an image determinationunit that determines whether or not a part of the object is excludedfrom the acquired image, in which the object has been detected from theacquired image but a part of the object is outside an imaging region ofthe image sensor; and a determination condition change unit that changesa determination condition used for determining whether or not theobjects represent the same object such that an object determined to beexcluded from the acquired image is easier to be determined as the sameobject compared to an object determined not to be excluded from theacquired image.

An object of which a part is located outside the imaging region of theimage sensor may have a second position detected from the acquired imagedifferently from a true position thereof.

In this regard, according to the above-described configuration of thepresent disclosure, it is determined whether or not a part of the objectdetected from the acquired image is included in the acquired image. Thatis, it is checked whether a part of the object is outside the imagingregion of the image sensor.

The determination condition is changed such that an object which isdetermined to be partially excluded from the acquired image can be moreeasily determined as the same object as an object obtained by theelectromagnetic wave sensor, compared to a case where an object isdetermined not to be partially excluded from the acquired image.

In this case, even when an error occurs in the second position because apart of the object is positioned outside the imaging region, it ispossible to minimize cases where the object from the acquired image isdetermined as a different object, and to minimize deterioration of thedetermination accuracy as to whether or not the objects represent thesame object.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the accompanying drawings, specific description will beprovided below to clarify the above object and other objects,characteristics and advantageous effects of the present disclosure.

In the accompanying drawings:

FIG. 1 is a diagram which describes a configuration of a vehicle controlapparatus;

FIG. 2 is a diagram which describes detection of an object;

FIG. 3 is a diagram which describes collision determination;

FIG. 4 is a diagram which describes detection of a second position;

FIG. 5 is a flowchart which describes a determination method as towhether or not the objects represent the same object;

FIG. 6 is a flowchart which shows in detail a process in step S13 ofFIG. 5;

FIG. 7 is a diagram which describes a method for determining apedestrian whose part is not included in an acquired image;

FIG. 8 is a diagram which describes the reliability of the determinationas to whether or not the objects represent the same object;

FIG. 9 is a diagram which describes the change of the determinationcondition;

FIG. 10 is a diagram which describes collision avoidance control in acomplementary mode according to a second embodiment;

FIG. 11 is a flowchart which describes the process of an ECU 20according to the second embodiment; and

FIG. 12 is a diagram which describes a method of calculating thereliability.

DESCRIPTION OF THE EMBODIMENTS

With reference to the drawings, embodiments of a vehicle controlapparatus and a vehicle control method will be described below. In thefollowing embodiments, components that are the same or equivalent toeach other are given the same reference signs in the drawings. For thecomponents having the same reference signs, descriptions in thespecification should be referred to previous ones.

First Embodiment

As shown in FIG. 1, the vehicle control apparatus 100 is mounted on avehicle and detects objects which are present in front of the vehicle.

Then, when there is a possibility that an object collides with thevehicle, the operation of avoiding the collision between the own vehicleprovided with the apparatus 100 and the object or the operation ofalleviating the collision is performed.

As shown in FIG. 1, the vehicle control apparatus 100 includes varioustypes of sensors 30, an ECU (Electronic Control Unit) 20, and a drivingsupport device 40.

The various types of sensors 30 are communicably connected to the ECU20, and outputs its detected results of objects to the ECU 20.

In FIG. 1, the various types of sensors 30 include an electromagneticwave sensor 31 and an image sensor 32 for acquiring images.

When, in the following description, it is necessary to distinguish anobject detected from by the electromagnetic wave sensor 31 and from anobject detected from the acquired images acquired by the image sensor32, the object detected by the electromagnetic wave sensor 31 isreferred to as an electromagnetic wave target, and the object detectedfrom the acquired image is referred to as an image target.

The electromagnetic wave sensor 31 is configured to transmit atransmission wave having directivity such as that gained by a millimeterwave, a radar, or the like. In addition, the electromagnetic wave sensor31 is configured to detect the position of an object or a relative speedwith respect to the own vehicle, based on a reflected wave reflectedfrom an electromagnetic wave target in response to the transmission ofthe transmission wave.

For example, the electromagnetic wave sensor 31 performs transmission ofa transmission wave or reception of a reflected wave by scanning theantenna in the horizontal direction with respect to the own vehicle.

The image sensor 32 is arranged in frontal part of the own vehicle CS,acquires an image viewed forward from the own vehicle CS, and outputsdata indicative of the acquired image to the ECU 20 at a predeterminedcycle.

The image sensor 32 is configured to include arrangement of a necessarynumber of image pickup devices such as a CCDs (Charge coupled devices)or the like vertically and horizontally. The necessary number depends ona desired resolution.

The respective images acquired by the image sensor 32 are formed bypixels corresponding to the resolution of the image sensor 32.

In this embodiment, the image sensor 32 is described as a single lenscamera, but a stereo camera may be used as the image sensor 32.

The ECU 20 is configured as a known computer including variouscomponents such as a CPU, a ROM, and a RAM.

The CPU is configured to, at intervals, execute programs previouslystored in the ROM, thereby realizing the functions for detecting objectswhich may be present in front of the own vehicle and determining thepossibility of collision of the own vehicle with such objects based onpositions of the detected objects.

Among functional units of the ECU 20, an object determining unit 23 isconfigured to determine whether or not objects represent the same objectbased on a determination condition. This determination condition isbased a first position at which an object which exists or may exist in afront view spreading in front of the own vehicle is detected by theelectromagnetic wave sensor 31 and a second position of an objectdetected from the acquired image obtained by capturing an object whichexists or may exist in a front view spreading in front of the ownvehicle by the image sensor 32.

In this embodiment, the object determining unit 23 includes a regioncondition determining unit 24 and a time condition determining unit 25,and determines whether or not objects represent the same object, basedon a determination condition set by the region condition determiningunit 24 and a determination condition set by the time conditiondetermining unit 25.

First, the first position and the second position, which are used fordetermining whether or not objects represent the same object, will nowbe described.

As shown in part (a) of FIG. 2, a first position Pr is a detectedposition of an object detected by the electromagnetic wave sensor 31,and is detected as a position on an XY plane. In this plane, the lateraldirection of the vehicle is assigned to the X direction and thetraveling direction of the vehicle is assigned to the Y direction.

The first position Pr includes, as information thereof, both a relativedistance r1 from the own vehicle to the object, and an azimuth θrcentered on the own vehicle.

In the XY plane of part (a) of FIG. 2, on the tip of the own vehicle CS,a position at which the electromagnetic wave sensor 31 is arranged isreferred as a reference point Po.

As shown in part (a) of FIG. 2, a second position is a detected positionof an object based on the acquired image, and is detected as a positionon the XY plane.

The second position Pi includes, as information thereof, both a relativedistance r2 from the own vehicle to an object and an azimuth θi centeredon the own vehicle, and is detected as a position on the XY planesimilarly to the first position Pr.

Of the second position, the relative distance r2 is calculated based onthe lower end of an object recognized in the acquired image.Specifically, from the acquired images, the object determining unit 23recognizes an object by pattern matching process using a dictionaryregistered in advance.

The dictionary is prepared for each type of object.

Further, as shown in part (b) of FIG. 2, of the second position, theobject determination unit 23 calculates a relative distance r2 based ona ratio between the length D1 to the length D2. The length D1 is alength from a position Pend of the lower end of an object recognized inthe acquired image to the lower end of the acquired image, whereas thelength D2 is a length from a vanishing point (Focus of Expansion; FOE)previously calculated in the acquired image to the lower end of theacquired image.

The position Pend of the lower end of the object in the acquired imagecan be calculated based on the number i in the horizontal direction andthe number j in the vertical direction of the pixels constituting theacquired image.

For example, when the coordinate (i, j) of the upper left apex O in theacquired image shown in part (b) of FIG. 2 is (0, 0), the length D1 canbe calculated by the number of pixels from the position Pend of thelower end of the object to the lower end of the acquired image in thevertical direction.

Similarly, the length D2 can be calculated by the number of pixels fromthe vanishing point FOE to the lower end of the acquired image in thevertical direction.

The calculation of the FOE in the acquired image is performed by a knownlearning process.

For example, the estimated position of the vanishing point FOE iscalculated by recognizing the partition lines LIN located on the leftand right sides of the own vehicle from the acquired image and obtainingthe intersection points on the extension lines of these partition linesLIN.

Then, a known optical flow is calculated for predetermined stationaryobjects or the like, and the estimated positions are corrected based onthe optical flow to learn an appropriate position of the vanishing pointFOE.

It is detected that stationary objects, such as a partition line, a treeor others, move to emerge from the vanishing point.

Therefore, the appearance points of these stationary objects aredetected a plurality of number of times, and learning is performed sothat the estimated position of the vanishing point FOE becomes anappropriate position based on each detected appearance point.

The region condition determination unit 24 is configured to determinewhether or not objects represent the same object by a determinationcondition. The determination condition is a condition that there must bea region overlapping both the electromagnetic wave search regioncalculated based on the first position and the image search regioncalculated based on the second position.

In part (a) of FIG. 2, since the region OL overlapping between theelectromagnetic wave search region Rr and the image search region Riexists, the region condition determination unit 24 determines that theelectromagnetic wave target and the image target represent the sameobject.

As shown in part (a) of FIG. 2, the electromagnetic wave search regionRr is a region having a width corresponding to a predefined possibleerror based on the characteristics of the electromagnetic wave sensor 31in each of the distance directions and each of the azimuth directionswith reference to the first position Pr.

For example, the electromagnetic wave search region Rr is set as a rangeextending by a possible error in the distance directions and a possibleerror in the angles in the azimuth directions with reference to thefirst position Pr(r1, θr).

The image search region Ri is a region having a width corresponding to apredefined possible error based on the characteristics of the imagesensor 32 in each of the distance directions and each of the azimuthdirections with reference to the second position Pi.

For example, in part (a) of FIG. 2, it is set as a region extendeddepending on a possible error in the distance directions and a possibleerror in the angles in the azimuth directions with reference to thesecond position Pi(r2, θi).

The time condition determination unit 25 is configured to determinewhether or not objects represent the same object. The determination ismade under a determination condition that a difference between anelectromagnetic wave prediction time TTC (Time to Collision) 1calculated by the first position and the second position, and an imageprediction time TTC2 is equal to or less than a determination thresholdThd.

As shown in part (a) of FIG. 3, the electromagnetic wave predicted timeTTC1 is an evaluation value indicating a remaining number of secondsbefore the own vehicle will collides with the electromagnetic wavetarget when the own vehicle continues to travel at the current speed.The evaluation value is calculated by dividing the relative distance r1extending from the own vehicle to the electromagnetic wave target, whichis calculated based on the first position, by the relative speed of theelectromagnetic wave target with respect to the own vehicle.

Further, the image predicted time TTC2 is an evaluation value indicatinga remaining number of seconds before the own vehicle collides with theimage target when the own vehicle continues to travel at the currentspeed. The evaluation value is calculated by dividing the relativedistance r2 extending from the own vehicle to the image targetcalculated based on the second position, by the relative speed of theimage target with respect to the own vehicle.

When the difference ΔTTC between the electromagnetic wave predictiontime TTC1 and the image prediction time TTC2 is equal to or smaller thanthe determination threshold Thd, it is determined that theelectromagnetic wave target and the image target represent the sameobject.

When the object determining unit 23 determines that the electromagneticwave target and the image target represent the same object, thecollision determination unit 26 is configured to fuse the first positionand the second position to calculate a single fusion (fused, i.e.,united) position which is new position information for the object whichhas been determined as the same object.

For example, a fusion position (r1, θi) is calculated by mutuallymerging the high-precision relative distance r1 derived from the firstposition (r1, θr) and the high-precision azimuth θi derived from thesecond position (r2, θi).

Hereinafter, when the object determination unit 23 determined the sameobject, the objects whose fusion positions have been calculated as afusion (fused, i.e. united) target.

In addition, the collision determination unit 26 is configured todetermine whether or not an object collides with the own vehicle basedon the plurality of fusion positions.

For example, the collision determination unit 26 calculates a movementtrajectory of an object determined as a fusion target based on aplurality of fusion positions having different time series, and extendsthe movement trajectory toward the own vehicle to calculate a futureposition of the object.

In part (b) of FIG. 3, the future position Fp is calculated by extendingthe movement trajectory calculated based on the fusion position, fromeach of the times t1 to t4 toward the own vehicle. When the calculatedfuture position is within a collision lateral position CSP which is setfor the own vehicle, it is determined that there is a possibility of acollision occurring between the object and the own vehicle.

The collision lateral position CSP is a range extending in the lateraldirection (X direction) from the center of the own vehicle in the frontportion of the own vehicle.

The collision determination unit 26 may determine whether or not anobject collides with the own vehicle by calculating the predictedcollision time TTC3 indicating the possibility that the own vehiclecollides with the object whose future position has been calculated. Thepredicted collision-time TTC3 is calculated by dividing the fusionposition indicating the current position of the object by the relativevelocity of the object relative to the own vehicle.

In addition to calculating the future position, the collisiondetermination unit 26 may calculate the position in the lateraldirection indicating the vehicle width of the object among the objectsdetermined as the fusion target, and determine the possibility of acollision occurring between the object and the own vehicle based on thelateral position.

The driving support device 40 is a warning device that emits a warningsound to the driver or a brake device that decelerates the speed of theown vehicle, and performs a collision avoidance operation and acollision reduction operation with an object based on a result ofdetermination by the collision determination unit.

If the driving support device 40 is a braking device, the automaticbraking is activated when it is determined that the own vehicle collideswith the fusion target.

If the driving support device 40 is a warning device, a warning sound isgenerated when it is determined that the own vehicle collides with thefusion target.

In part (a) of FIG. 4 shows an electromagnetic wave detection region A1which is a field region in front of the own vehicle, in which an object(a first object) can be detected by the electromagnetic wave sensor 31,while an imaging region A2 which is a field region in front of the ownvehicle, in which an image with an object (a second object) can beacquired by the image sensor 32.

In this embodiment, the imaging region A2 is a region narrower in thefront/rear direction in front of the own vehicle than theelectromagnetic wave detection region A1.

In addition, among the regions lying in front of the own vehicle, aregion located in the vicinity and a region located in the distance areregions in each of which an object can be detected by theelectromagnetic wave sensor 31, but cannot be recognized from theacquired image acquired by the image sensor 32.

Therefore, if an object is positioned at each of the positions in thevicinity field and the distant field in front of the own vehicle, thefirst position can be detected, but the second position cannot bedetected.

The second position of the object detected using the acquired images iscalculated based on the position of the lower end of the objectrecognized in the acquired images.

In this calculation, since the lower part of the object positioned infront of the own vehicle is positioned outside the imaging region A2 ofthe image sensor 32, even when a part of the object is not included inthe acquired image, the object determination unit 23 may recognize animage target Gb by the pattern matching process as shown in part (b) ofFIG. 4.

In such a case, the second position Pie of the object is calculatedbased on the position of the lower end of the acquired images.

Therefore, the second position Pie, which is calculated in a state wherethe lower part of the object is not included in the acquired images, iscalculated at a position different from a true value (position) Pit.

In such a case, when a deviation between the object detected from thesecond position and the object detected from the first position becomeslarge, these two detected objects which represent the same object mayerroneously be determined as mutually different objects.

Therefore, in the present embodiment, the ECU 20 includes an imagedetermination unit 21 and a determination condition changing unit 22.

Since an object is detected from the acquired images but a part of theobject is outside the imaging region of the image sensor 32, the imagedetermination unit 21 determines whether or not the part of the objectis partially excluded from the acquired image.

In this embodiment, since the second position is calculated based on theposition of the lower end portion of the object, the image determinationunit 21 determines whether or not the lower part of the object isoutside the imaging region.

The determination condition changing unit 22 is configured to change thedetermination condition such that the object determined by the imagedetermination unit 21 to be partially excluded from the acquired imagecan be determined more easily to be the same object, compared with anobject determined not to be partially included in the acquired image.

In the present embodiment, the determination condition changing unit 22enlarges the image search region in the distance direction such that theimage search region and the electromagnetic wave search region caneasily overlap with each other. This allows the detected objects to bedetermined as being the same object.

Further, by increasing the determination threshold for comparing thedifference between the electromagnetic wave prediction time and theimage prediction time, it becomes easier to determine that the detectedobjects represent the same object.

With reference to FIG. 5, how a determination method is performed by theECU 20 will now be described, practically, in terms of whether or notobjects represent the same object. The process shown in FIG. 5 isperformed at a predetermined cycle by the ECU 20.

In this example, there is described a case where a pedestrian positionedin front of the own vehicle is a target to be detected, i.e., adetection target.

First, in step S11, a first position, which is a detection result of theelectromagnetic wave target by the electromagnetic wave sensor 31, isacquired.

In step S12, the second position, which is the detection result of theimage target by the acquired image, is acquired.

In step S13, it is determined whether or not the pedestrian whose secondposition has been detected becomes a target to which the determinationcondition of the same determination is to be changed.

FIG. 6 is a flowchart illustrating the process of step S13 in detail. Inthe process shown in FIG. 6, a pedestrian is set as a detection target,where the pedestrian's legs are not included in the acquired image dueto a pedestrian's positional approach to the own vehicle.

In step S31, the direction of the positional changes of the pedestrianon the acquired images is determined for the pedestrian to which thesecond position has been detected.

Specifically, a feature point of the pedestrian to which the secondposition has been detected is extracted, and the direction of thepositional changes of the pedestrian on the acquired images isdetermined based on an optical flow indicating a time-series change ofthe feature points.

For example, an edge point indicating a contour of the pedestrian can beused as the feature point.

Step S31 functionally corresponds to the direction determination unit.

If the direction of the positional changes of the pedestrian on theacquired images is downward, it can be determined that the pedestrian isapproaching the own vehicle.

On the other hand, if the direction of the positional changes on theacquired images of the pedestrian is other than the downward direction,it can be determined that the pedestrian is moving away from the ownvehicle.

In this embodiment, when the direction of the positional changes of thepedestrian on the acquired images is detected as the lateral directionor the upward direction, the ECU 20 determines that the direction of thepositional changes is other than the downward direction.

If the direction of the positional changes of the pedestrian on theacquired images is other than the downward direction (NO in step S31),the process shown in FIG. 6 is terminated and the process returns toFIG. 5 because the pedestrian is not approaching the own vehicle.

On the other hand, if the direction of the positional changes of thepedestrian on the acquired images is downward (YES in step S31), sincethe pedestrian is approaching the own vehicle, in step S32, it isdetermined whether or not the legs, which compose the lower portion ofthe pedestrian, is included in the acquired images, i.e., the overallpedestrian is included in the acquired images.

For example, the ECU 20 includes a dictionary for recognizing the upperbody and the lower body of a pedestrian among dictionary data used forpattern matching.

Therefore, by using both dictionary data for the upper body anddictionary data for the lower body of the pedestrian, it is determinedwhether or not the legs of the pedestrian is not included. Specifically,even if a pedestrian whose upper body is recognized by the dictionaryfor the upper body but this pedestrian's lower body cannot be recognizedby the dictionary for the lower body, it is determined that thepedestrian's legs are not included in the currently acquired image.

Step S32 functionally corresponds to an image determination process.

In the dictionary for the upper body of the pedestrian, predicablefeature amounts, which correspond to the head and the body of thepedestrian, are registered.

Accordingly, as shown in parts (a) and (b) of FIG. 7, using thepedestrian's upper body dictionary, at least, the head Gbh and the bodyGbb of the pedestrian is recognized in the acquired images.

In the dictionary for the lower body of the pedestrian, feature amountswhich correspond to the legs of the pedestrian are registered.

Therefore, by performing the pattern matching using the dictionary forthe lower body, the pedestrian with their legs GbL included in the imageis recognized, as shown in part (a) of FIG. 7, but the pedestrian withtheir legs GbL not included in the image is not recognized, as shown inpart (b) of FIG. 7.

Note that the respective feature amounts of the head, body, and legsused in the dictionary may be updated to optimum values based on a knownlearning process, not limited to using fixed values.

If the legs of the pedestrian are included (NO in step S32), the processshown in FIG. 6 is terminated, and the process returns to FIG. 5.

On the other hand, if the legs of the pedestrian are not included (YESin step S32), it is determined in step S33 that the lower part of thepedestrian is outside the imaging region.

For example, a status flag indicating that the lower part of thepedestrian is outside the imaging region is set to a true value, thenthe process shown in FIG. 6 is terminated.

Returning to FIG. 5, in step S14, the reliability of the samedetermination for the pedestrian based on the first position and thesecond position is calculated.

In a case where the determination condition is unnecessarily changedunder a low reliability of the same-object determination, accuracy ofthe determination may be lowered further on the contrary to controlpurpose.

In the embodiment, the reliability is an index value indicating thelikelihood of the same-object determination performed based on the firstposition and the second position. In the first embodiment, the ECU 20 isconfigured to calculate the reliability based on the number of times howmany the pedestrian has been continuously determined as being the sameobject in the processes performed prior to the current process.

The reason is that the possibility that the image target and theelectromagnetic wave target represent the same object increases, becausea large number of times of determination indicates that the same-objectdetermination has been stably performed.

Step S14 functionally corresponds to the reliability calculation unit.

As shown in FIG. 8, in this embodiment, as the number of times thatpedestrians has been determined to be the same object increases, thevalue of the reliability is set to be increased.

For example, the ECU 20 records map information indicating arelationship between the reliability and the number of times determinedas the same object, which is shown in FIG. 8, and acquires thereliability based on this map information.

If the reliability calculated in step S14 is less than a threshold Th1(NO in step S15), the process proceeds to step S19.

On the other hand, if the reliability calculated in step S14 is equal toor greater than the threshold Th1 (YES in step S15), the processproceeds to step S16, and a value of the status flag is determined.

The threshold Th1 is a threshold for determining the reliability.

If the status flag, which indicates that the lower part of thepedestrian is not included in the current acquired image, is false (NOin step S16), the process proceeds to step S19.

On the other hand, if the status flag is true (YES in step S16), insteps S17 and S18, the determination condition is changed so that thepedestrian who has been determined that the lower part is not includedin the acquired image can be more easily determined as the same objectthan a pedestrian who has been determined that the pedestrian's lowerpart is included in the acquired image.

Therefore, steps S17 and S18 functionally correspond to thedetermination condition changing process.

First, in step S17, the image search region is enlarged in the distancedirection with respect to the pedestrian whose lower part is determinednot to be included in the acquired image, compared with a pedestrianwhose lower part is determined to be included in the acquired image.

In this embodiment, as shown in part (a) of FIG. 9, the length of thelegs of the pedestrian, which is not included in the acquired image, iscalculated, and an estimation value of the position Pend of the lowerend of the pedestrian located outside the imaging region is calculatedbased on the calculated length of the legs.

Then, based on the calculated position Pend of the lower end, anenlargement amount of the image search range in the distance directionis calculated.

As a method of calculating the length of the legs which are not includedin the acquired image, for example, the ECU 20 recognizes the lengths ofthe head and the body of the pedestrian by using a known patternmatching process based on the acquired image, and calculates the lengthof the legs which are not included in the acquired image based on theratio of the lengths of the recognized portions.

Then, as shown in part (b) of FIG. 9, the image search range is enlargedin the distance direction in accordance with the estimated position ofthe lower end.

In this embodiment, the longer the length from the lower end in theacquired image to the estimated position of the pedestrian's lower end,the greater the amount of enlargement in the distance direction in theimage search range.

In part (b) of FIG. 9, the image search range is enlarged to the sidecloser to the own vehicle in the distance direction.

In step S18, the determination threshold Thd is increased to make iteasier for a pedestrian, whose lower part is determined to be onlypartially included in the acquired image, to be determined as the sameobject as a pedestrian whose lower part is determined to be included inthe acquired image.

For example, the ECU 20 estimates the position of the lower end portionof the pedestrian, which lower end portion is positioned outside theimaging region. Then, the determination threshold Thd is increased basedon the estimated position of the lower end portion.

Therefore, as the length estimated from the lower end of the acquiredimage to the lower end of the pedestrian is longer, an increased amountof the determination threshold Thd is set to be larger.

In step S19, it is determined whether or not the electromagnetic wavetarget detected at the first position represent the same object as theimage target detected at the second position.

In this embodiment, the same-object determination for the pedestrians isperformed when both the determination condition of whether or not thereis a region overlapping with each search region and the determinationcondition of whether or not the difference between the number ofprediction times is equal to or less than the determination thresholdThd are satisfied.

When the determination condition is changed in steps S17 and S18, it isfurther determined whether or not the objects represent the same basedon the changed determination condition.

Therefore, by enlarging the image search region in the distancedirection, it is more likely to generate a region overlapping with theelectromagnetic wave search region.

Further, by increasing the determination threshold Thd, it becomes easyto determine that the difference between the electromagnetic waveprediction time and the image prediction time is smaller thedetermination threshold Thd.

When the determination condition for the same-object determination isestablished (YES in step S19), in step S20, the establishment flagindicating that the determination is established is set to be true.

On the other hand, when the determination that the objects are the sameis not established (NO in step S19), the establishment flag is set to befalse in step S21.

When the process of step S20 or step S21 is terminated, the process ofFIG. 5 is temporarily terminated.

Therefore, if the establishment flag is true in step S20, a fusionposition obtained by merging the first position and the second positionwith respect to the same pedestrian is calculated. On the other hand, ifthe establishment flag is false in step S21, the fusion position is notcalculated.

Steps S19 to S21 functionally correspond to the object determinationprocess.

The first embodiment described above has the following effects.

The ECU 20 determines whether or not a body part of the pedestrian isnot included in the acquired image due to the fact that the body part ofthe pedestrian who has been detected at the second position is outsidethe imaging region of the image sensor 32.

Then, the determination condition is changed such that an object whichis determined to be partially included in the acquired image can bedetermined as the same object easily, compared with an object which isdetermined to be included in the acquired image.

In this case, even when a part of an object is deviated from the imagingregion so that the second position is erroneously detected, it can beavoided as much as possible that that object is erroneously determinedas another object. It is therefore possible to reduce a decrease in theaccuracy for the same-object degermation.

An object whose part is not included in the acquired image due to itsposition being closer to the own vehicle has a higher possibility ofcolliding with the own vehicle, compared to an object whose part is notincluded in the acquired image due to its position being distant.

In this regard, in the above-described configuration, on condition thatthe direction of the positional changes of the object on the acquiredimages is determined to be downward, the ECU 20 changes thedetermination condition so that the object determined to be partiallyincluded in the acquired image is more easily determined to be the sameobject than an object determined not to be partially included in theacquired image.

In this case, unnecessary operations of the collision avoidance controldue to the relaxation of the determination condition can be minimized bychanging the determination condition, so that it becomes easy to performthe same-object determination by limiting the distance from the ownvehicle to an object that is approaching.

When both an electromagnetic wave search region and an image searchregion which extend in a predetermined range in the distance directionand the azimuth direction are calculated, and the existence of anoverlapping region in each of the calculated search regions is used as adetermination condition, the accuracy in obtaining the second positionmay be lowered. In such a case, the range in the distance direction ofthe image search region is not properly calculated and there is apossibility that the two search regions do not overlap with each other.

In this respect, in the above-described configuration, the ECU 20enlarges the image search region in the distance direction, such that itis easier to the same-object determination can be performed based on theobject that is determined to be partially excluded from the acquiredimage, compared to be based on an object that is determined not to bepartially excluded from the acquired image.

In this case, the necessary procedure is to change the image searchregion in the distance direction with respect to the object determinedto be partially excluded from the acquired image, and it is possible toeasily determine that both objects represent the same object, by asimple method.

There is a probable case where the determination condition, which is acondition for determining whether or not the objects represent the sameobject, is that the difference between the electromagnetic waveprediction time calculated based on the first position and the imageprediction time calculated based on the second position is equal to orless than the determination threshold. In such a case, if thecalculation accuracy of the second position is low, an error occurs inthe image prediction time calculated based on the second position, andthe difference from the electromagnetic wave prediction time may becomelarger.

In this respect, in the above-described configuration, the ECU 20increases the determination threshold with respect to the objectdetermined to be partially excluded from the acquired image, therebymaking it easier to determine the objects represent the same object,compared to an object determined not to be partially excluded inacquired images.

In this case, the determination threshold may be increased for an objectdetermined to be partially excluded from the acquired image, and thesame-object determination can be easily performed by a simplifiedmethod.

When the determination condition is unnecessarily changed under a lowreliability for same-object determination, accuracy of the determinationmay be lowered on the contrary to control purpose.

In this regard, in the above-described configuration, the ECU 20 changesthe determination condition for the object determined to be partiallyinterrupted from the acquired image on the condition that thereliability is equal to or higher than the predetermined value.

In this case, deterioration in the determination accuracy, which iscaused by changes of the determination condition, may be minimized.

Second Embodiment

In the second embodiment, in the process shown in FIG. 5, when an imageloss occurs in a state where the second position is not detected afterthe objects are determined to be the same, the same-object determinationis performed easier for the object whose lower part is not included inacquired images, compared to an object whose lower part is included inacquired images.

The image loss is a phenomenon in which the first position iscontinuously detected and the second position is not detected, after theobjects have been determined to be the same.

First, the collision avoidance control performed when an image lossoccurs will now be described.

In parts (a) and (b) of FIG. 10, there are provided diagrams eachillustrating differences in braking force of the automatic brake, as anexample of the collision avoidance control.

In part (a) of FIG. 10, the horizontal axis represents the time “sec”,and the vertical axis represents transitions of the vehicle speed “V”,whereby the braking force of the automatic brake is represented by aninclination of decrease amounts of the vehicle speed V after theautomatic brake has been operated. That is, the greater the inclination,the higher the braking force of the automatic brake.

Objects previously determined to be the same may be present in front ofthe own vehicle, even when the second position is not detected. For thisreason, with respect to the object in which the image loss has occurred,the ECU 20 continues the same-object determination for a predeterminedperiod.

In addition, in a period in which the determination as the same objectis continued after the image loss, the collision avoidance control isperformed in a complementary mode.

In part (a) of FIG. 10, the braking force of the automatic brake islowered for the object in which the image loss occurs, as compared withan object in which the image loss does not occur.

As an alternative, as the collision avoidance control, when the drivingsupport device 40 emits a warning sound, the volume of the warning soundgenerated when an image loss occurs may be made smaller than a volume ofthe warning sound generated when the image loss does not occur.

The process of the ECU 20 according to the second embodiment will now bedescribed with reference to FIG. 11.

The process shown in FIG. 11 is a process performed by the ECU 20 at apredetermined cycle, after the performance of the same-objectdetermination. In the second embodiment, a case where a pedestrian istargeted as an object will be described as an example.

In step S41, it is determined whether or not a pedestrian has beensubjected to the same-object determination in the past.

For example, it is determined whether or not the establishment flag istrue to indicate that the pedestrian has been determined as the fusiontarget. If it is determined that the pedestrian is not the fusion target(NO in step S41), the process of FIG. 11 is temporarily terminated.

If it is determined that pedestrians have represented the samepedestrian (YES in step S41), the establishment condition for the imageloss is determined in step S42. Specifically, the establishmentcondition for the image loss is that the first position is continuouslydetected with respect to the object but the second position is notdetected.

If the image loss is not caused (NO in step S42), the process of FIG. 11is temporarily terminated.

Step S42 functionally corresponds to the image loss determination unit.

If an image loss has occurred (YES in step S42), the setting of acomplementary mode to be executed for the pedestrian in which the imageloss has occurred is performed in steps S43 to S48.

In this embodiment, both the ease of operations of the collisionavoidance control and the duration of the continuous same-objectdetermination of an object in which the image loss has occurred are set.

In step S43, the reliability indicating the reliability of thesame-pedestrian determination is calculated.

In the second embodiment, as in S14 of FIG. 5, the ECU 20 alsodetermines the reliability based on the number of times thedetermination of the fusion target continues.

When the reliability is equal to or higher than a threshold Th11 (YES instep S44), it is further determined in step S45 whether or not the lowerpart of the pedestrian is outside an acquired image.

In the second embodiment, the ECU 20 also determines whether or not thelower part of the pedestrian is included in the acquired image by usingboth the dictionary for the upper body and the dictionary for the lowerbody.

An image loss occurs when an object moves from within the imaging regionof the electromagnetic wave sensor 31 to outside of the imaging region,so that the ECU 20 cannot recognize the object from the acquired image.

When the object is approaching the own vehicle, the area of the lowerpart of the pedestrian that is excluded from the imaging regionincreases in accordance to movements of the object. Therefore, it wouldbe difficult for the ECU 20 to recognize the object.

Therefore, there is a high possibility that an object whose lower partis determined not to be included in the acquired image and whose imagedetermined to have an image loss is located in the vicinity of the ownvehicle.

On the other hand, for example, when the object moves laterally awayfrom the own vehicle, parts other than the lower part are excluded fromthe acquired image in accordance with movements of the object, so thatthe ECU 20 cannot recognize the object.

Therefore, it is highly probable that a pedestrian who has beendetermined that the lower part thereof is included in the acquired imagebut has suffered from having the image loss is moving in a directionaway from the own vehicle, being outside the imaging region.

When it is determined that the lower part of the pedestrian is excludedfrom the acquired image (YES in step S45), the process in step S46 isperformed. In this process, the collision avoidance control for thepedestrian whose lower part is determined to be not included in theacquired image is carried out. This collision avoidance control isperformed easier to operate, compared to collision avoidance control forthe pedestrian whose lower part is determined to be included in theacquired image.

For example, when the automatic brake is operated as the collisionavoidance control, as shown in part (a) of FIG. 10, the braking force ofthe automatic brake for the pedestrian whose lower part is determinednot to be included in the acquired image is made higher than a brakingforce of the automatic brake for the pedestrian whose lower part isdetermined to be included in the acquired image.

In addition, as the collision avoidance control, when the drivingsupport device 40 emits a warning sound, the volume of the warning soundfor the pedestrian whose lower part is determined to be only partiallyincluded in the acquired image among the pedestrians in which the imageloss occurs is made higher than the volume of the alarm sound for thepedestrian whose lower part is determined to be fully included in theacquired image.

On the other hand, when the reliability is less than the threshold Th11(NO in step S44) or when it is determined that the lower part of thepedestrian is not excluded (NO in step S45), the process in step S48 isperformed. In this process, the collision avoidance control for thepedestrian whose lower part is determined to be fully included in theacquired image is made harder to operate, compared to the collisionavoidance control for the pedestrian whose lower part is determined notto be included in the acquired image.

Therefore, when the automatic braking is performed as the collisionavoidance control, as shown in part (a) of FIG. 10, the braking force ofthe automatic braking is made lower than the braking force of theautomatic braking for the pedestrian whose lower part is excluded fromthe acquired image.

In addition, when a warning sound is generated as the collisionavoidance control, the volume of the warning sound is set lower than thevolume of the warning sound for the pedestrian whose lower part is notincluded in the acquired image.

Steps S46 and S48 functionally correspond to the control unit.

In step S47, the pedestrian whose lower part is determined not to beincluded in the acquired image and whose image loss is determined tooccur is made easier to continue the same-object determination, comparedto the pedestrian whose lower part is determined to be included in theacquired image and whose image loss is determined to occur.

In this embodiment, by changing duration of the complementary modelonger, it makes easier to continue the same-object determination.

Step S47 functionally corresponds to the continuation condition changingunit.

When the process of step S47 or S48 is terminated, the process shown inFIG. 11 is temporarily terminated.

The second embodiment described above has the following effects.

It is highly likely that the object determined that the lower partthereof is excluded from the acquired image and that the image loss hasoccurred is located in the vicinity of the own vehicle, and the objectdetermined that the lower part is not excluded from the acquired imageand that the image loss has occurred is moving in the direction awayfrom the own vehicle.

In this regard, in the above configuration, the ECU 20 makes it easierto continue the same-object determination for an object which isdetermined that the lower portion thereof is only partly included in theacquired image and that the image loss has occurred, compared with anobject determined that the lower portion is included in the acquiredimage and that the image loss has occurred.

In this case, for an object that is highly likely to be present in frontof the own vehicle, it becomes easier to continue the determination ofwhether the objects represent the same object, even after occurrence ofthe image loss. This reduces the collision avoidance control for theobject from being stopped.

Even when objects are determined to be the same, if the reliability ofthis determination is low, it is easy to continue the same-objectdetermination after occurrence of the image loss, which however resultsin causing one reason for non-operation of the collision avoidancecontrol.

In this regard, in the above-described configuration, the ECU 20determines that the lower part is not included in the acquired image anddetermines that the image loss has occurred, on condition that thereliability of the same-object determination is equal to or higher thanthe threshold, which makes it easier to continue the determination,compared with an object determined that the lower part thereof isincluded in the acquired image and that the image loss has occurred.

In this case, it is possible to minimize unnecessary operations of thecollision avoidance control by continuing the same-object determinationafter occurrence of the image loss and by limiting the determination toa case where the reliability of the determination is high.

An object which has been subjected to occurrence of an image lossbecause the lower portion is not included in the acquired image is morelikely to be positioned in front of the own vehicle even after the imageloss, compared to an object in which an image loss occurs withoutdetermining that the lower portion is not included in the acquiredimage.

In this regard, in the above-described configuration, the ECU 20 makesit easier to operate the collision-avoidance control for an object whoselower portion is determined not to be included in the acquired image andwhose image loss is determined to occur, as compared with an objectwhose lower portion is determined to be included in the acquired imageand whose image loss is determined to occur.

In this case, it is possible to reduce the possibility that thecollision avoidance control is inactive. The collision avoidance controlis for an object which is likely to be in front of the own vehicle amongthe objects in which the image loss has occurred.

Other Embodiments

In the case where the same-object determination can be performed basedon the determination condition which needs a difference between theelectromagnetic wave prediction time TTC1 calculated by the firstposition and the image prediction time TTC2 calculated by the secondposition to be larger than the determination threshold, the reliabilitycalculated in step S14 of FIG. 5 or step S43 of FIG. 11 may becalculated based on the difference between the respective predictiontimes.

In this case, as shown in part (a) of FIG. 12, the smaller thedifference ΔTTC between the prediction times, the higher the reliabilityis calculated. For example, the ECU 20 records map informationindicating the relationships between the reliability and the differenceΔTTC shown in part (a) of FIG. 12, and acquires the reliability based onthe map information.

The reliability of the same-object determination may be calculatedaccording to the distance from the own vehicle to an object. In thiscase, when the distance from the own vehicle to the object is short, thedetection accuracy of the object detected by the electromagnetic wavesensor 31 is lowered, while when the distance from the own vehicle tothe object is long, the detection accuracy of the object detected fromthe acquired image is lowered.

Therefore, as shown in part (b) of FIG. 12, in the short distance wherethe distance from the own vehicle to the object is equal to or less thana preset length L1, the shorter the distance, the lower the reliability.

Further, in a long distance in which the distance from the own vehicleto the object is equal to or greater than another preset length L2, thereliability is set to a higher value as the distance becomes longer.Note that the distance L2 is longer than the distance L1 from the ownvehicle.

As another method of changing the determination condition, in additionto enlarging the image search region in the distance direction, theimage search region may be offset in the distance direction on the XYplane.

In this case, in S17 of FIG. 5, the ECU 20 estimates the length of thelower part of the object that is not included in the acquired image, andcalculates the position of the lower end of the object based on theestimated length of the lower part. Then, based on the calculatedposition of the lower end, an amount of the offset which offsets theimage search range in the distance direction is calculated.

Instead of changing the enlargement amount of the image search region bythe length of the lower portion which is partly included in the acquiredimage, the enlargement amount may be increased by a predeterminedamount.

The second position may be calculated based on the position of the lowerend and the position of the upper end of the object, in addition to thecalculation based on the position of the lower end of the objectrecognized in the acquired image.

In this case, in addition to determining whether or not the lower partis not included in the acquired image as a part of the object, it may bedetermined that the part of the object is not included in the acquiredimage when the upper part of the object is not included in the acquiredimage.

As the determination condition of whether or not objects represent thesame object, any one of determination conditions may be used. Suchdetermination conditions are whether or not each search region overlaps,the determination of whether or not each prediction time is equal to orless than the determination threshold, and a combined use ofdetermination for the search region overlap and the predation times.

In this case, in step S19 of FIG. 5, the determination as to whether ornot the objects are the same is performed depending on whether eachsearch region overlaps or whether a difference in the prediction timesis equal to or less than the determination threshold.

In the second embodiment, as another example of facilitating theoperations of the collision-avoidance control by the ECU 20, theoperation of the autobrake may be advanced in timing.

In this instance, the ECU 20 makes it easier to operate thecollision-avoidance control by temporally advancing the operationtimings of the automatic braking of the object determined that the lowerpart is not included in the acquired image and that the image loss hasoccurred, as compared with an object determined that the lower part isincluded in the acquired image and that the image loss has occurred.

As another example of facilitating the operations of thecollision-avoidance control by the ECU 20, the operation of the warningsound may be made earlier in timing.

As an antiinvasive to the object set forth in the foregoing embodiments,a bicycle may be assigned, instead of a pedestrian who serves as anobject for the same-object determination. In this case, the ECU 20 usesa dictionary for bicycles instead of a dictionary for pedestrians.

The present disclosure has been described by way of examples; however,the present disclosure should not be construed as being limited to suchexamples or structures. The scope of the present disclosure shouldencompass various modifications or equivalents. In addition, variouscombinations or modes, and even other combinations or modes includingone or more elements or one or less elements should fall within thescope and spirits of the present disclosure.

1. A vehicle control apparatus comprising: an object determination unitthat determines whether or not an object at a first position and anobject at a second position represent a same object based on the firstposition at which the object which exists in front of a own vehicle isdetected by an electromagnetic wave sensor and the second position ofthe object detected from an image of a forward view of the own vehicle,the image being acquired by an image sensor; an image determination unitthat determines whether or not a part of the object is excluded from theacquired image, in which the object has been detected from the acquiredimage but a part of the object is outside an imaging region of the imagesensor; and a determination condition change unit that changes adetermination condition used by the object determination unit indetermining whether or not the objects represent the same object, whichdetermination is performed by the object determination unit, such thatan object determined to be excluded from the acquired image is easier tobe determined as the same object compared to an object determined not tobe excluded from the acquired image.
 2. The vehicle control apparatusaccording to claim 1, further comprising: a direction determination unitthat determines a direction of positional changes of the object on theacquired image based on a plurality of the acquired images acquired atdifferent times, wherein the determination condition changing unit thatchanges the determination condition on condition that the direction ofthe positional changes of the object on the acquired images isdetermined to be downward, such that the object determined to bepartially excluded from the acquired image is more easily determined tobe the same object in comparison with an object a part of which isdetermined not to be excluded in the acquired image.
 3. The vehiclecontrol apparatus according to claim 1, wherein the object determinationunit calculates an electromagnetic wave search region and an imagesearch region, and sets, to the determination condition, a conditionthat there is a region which overlaps on both the calculatedelectromagnetic wave search region and the calculated image searchregion, the electromagnetic wave search region being a predeterminedrange i) defined based on, as a reference, the first position and ii)extending in both a direction along the distance from the own vehicle tothe object and an azimuth direction from the own vehicle to the object,the image search region being a predetermined range defined based on, asa reference, the second position extending in the direction along thedistance and the azimuth direction; and the determination conditionchanging unit enlarges the image search region in the direction alongthe distance such that the object determined to be partially excludedfrom the acquired image is more easily determined to be the same objectin comparison with an object a part of which is determined not to beexcluded in the acquired image.
 4. The vehicle control apparatusaccording to claim 1, wherein the object determination unit calculatesi) based on a first position, an electromagnetic wave prediction timewhich is a predicted time until the object collides with the own vehicleand ii) based on the second position, an image prediction time which isa predicted time until the object collides with the own vehicle; andsets, to the determination condition, a condition that the differencebetween the electromagnetic wave prediction time and the imageprediction time is equal to or less than the predetermined threshold;and the determination condition changing unit enlarges the predeterminedthreshold such that the object determined to be partially excluded fromthe acquired image is more easily determined to be the same object incomparison with an object a part of which is determined not to beexcluded in the acquired image.
 5. The vehicle control apparatusaccording to claim 1, further comprising a reliability calculation unitfor calculating a reliability of the same determination of the objects,which is based on the first position and the second position, whereinthe determination condition changing unit changes the determinationcondition on condition that the reliability is equal to or greater thana predetermined value, such that the object determined to be partiallyexcluded from the acquired image is more easily determined to be thesame object in comparison with an object a part of which is determinednot to be excluded in the acquired image.
 6. The vehicle controlapparatus according to claim 2, wherein the image determination unitdetermines whether or not a lower part of the object is excluded fromthe acquired image, wherein the image determination unit comprises: animage loss determination unit that determines an object caused an imageloss, provided that the object is first subjected to determination ofthe same object, and the first position is then continuously detectedand the second position is not detected; and a continuation conditionchanging unit that makes it easier to continue the same-objectdetermination for the object determined that the lower part thereof isexcluded from the acquired image and the image loss is caused, comparedwith an object determined that the lower part thereof is not excludedfrom the acquired image and the image loss is caused.
 7. The vehiclecontrol apparatus according to claim 6, further comprising: areliability calculation unit for calculating, for the object caused theimage loss, a reliability of the same determination for the objectsbased on the first position and the second position provided before theimage loss occurs, wherein the continuation condition changing unit, onthe condition that the reliability is equal to or greater than apredetermined value, makes it easier to continue the same-objectdetermination for the object determined that the lower part thereof isexcluded from the acquired image and the image loss is caused, comparedwith an object determined that the lower part thereof is not excludedfrom the acquired image and the image loss is caused.
 8. The vehiclecontrol apparatus according to claim 6, further comprising: a controlunit that performs collision avoidance control for avoiding collision ofthe own vehicle with objects determined as the same object, wherein thecontrol unit that makes it easier to operate the collision avoidancecontrol for the object determined that the lower part thereof isexcluded from the acquired image and the image loss is caused, comparedwith an object determined that the lower part thereof is not excludedfrom the acquired image and the image loss is caused.
 9. A vehiclecontrol method including: an object determination process thatdetermines whether or not an object at a first position and an object ata second position represent a same object based on the first position atwhich the object which exists in front of a own vehicle is detected byan electromagnetic wave sensor and the second position of the objectdetected from an image of a forward view of the own vehicle by an imagesensor, the object determination process being performed by a vehiclecontrol apparatus; an image determination process that determineswhether or not a part of the object is excluded from the acquired image,in which the object has been detected from the acquired image but a partof the object is outside an imaging region of the image sensor, theimage determination process being performed by the vehicle controlapparatus; and a determination condition change process that changes adetermination condition used by the object determination process fordetermining whether or not the objects represent the same object, whichdetermination is performed by the object determination unit, such thatan object determined to be excluded from the acquired image is easier tobe determined as the same object compared to an object determined not tobe excluded from the acquired image, the determination condition changeprocess being performed by the vehicle control apparatus.
 10. A vehiclecontrol apparatus comprising: an object determination unit thatdetermines whether or not an object at a first position and an object ata second position represent a same object based on the first position atwhich the object which exists in front of a own vehicle is detected byan electromagnetic wave sensor and the second position of the objectdetected from an image of a forward view of the own vehicle, the imagebeing acquired by an image sensor; an image determination unit thatdetermines whether or not a part of the object is excluded from theacquired image, in which the object has been detected from the acquiredimage but a part of the object is outside an imaging region of the imagesensor; and a determination condition change unit that changes adetermination condition used by the object determination unit indetermining whether or not the objects represent the same object, whichdetermination is performed by the object determination unit, such thatan object determined to be excluded from the acquired image is easier tobe determined as the same object compared to an object determined not tobe excluded from the acquired image, wherein the image determinationunit determines whether or not a lower part of the object is excludedfrom the acquired image, and the image determination unit comprises: animage loss determination unit that determines an object caused an imageloss, provided that the object is first subjected to determination ofthe same object, and the first position is then continuously detectedand the second position is not detected; and a continuation conditionchanging unit that makes it easier to continue the same-objectdetermination for the object determined that the lower part thereof isexcluded from the acquired image and the image loss is caused, comparedwith an object determined that the lower part thereof is not excludedfrom the acquired image and the image loss is caused.
 11. A vehiclecontrol method performed by a vehicle control apparatus, the methodcomprising: an object determination process that determines whether ornot an object at a first position and an object at a second positionrepresent a same object based on the first position at which the objectwhich exists in front of a own vehicle is detected by an electromagneticwave sensor and the second position of the object detected from an imageof a forward view of the own vehicle, the image being acquired by animage sensor; an image determination process that determines whether ornot a part of the object is excluded from the acquired image, in whichthe object has been detected from the acquired image but a part of theobject is outside an imaging region of the image sensor; and adetermination condition change process that changes a determinationcondition used by the object determination process in determiningwhether or not the objects represent the same object, whichdetermination is performed by the object determination process, suchthat an object determined to be excluded from the acquired image iseasier to be determined as the same object compared to an objectdetermined not to be excluded from the acquired image, wherein the imagedetermination process determines whether or not a lower part of theobject is excluded from the acquired image, and the image determinationprocess comprises: an image loss determination process that determinesan object caused an image loss, provided that the object is firstsubjected to determination of the same object, and the first position isthen continuously detected and the second position is not detected; anda continuation condition changing process that makes it easier tocontinue the same-object determination for the object determined thatthe lower part thereof is excluded from the acquired image and the imageloss is caused, compared with an object determined that the lower partthereof is not excluded from the acquired image and the image loss iscaused.
 12. The vehicle control apparatus according to claim 2, whereinthe object determination unit calculates an electromagnetic wave searchregion and an image search region, and sets, to the determinationcondition, a condition that there is a region which overlaps on both thecalculated electromagnetic wave search region and the calculated imagesearch region, the electromagnetic wave search region being apredetermined range i) defined based on, as a reference, the firstposition and ii) extending in both a direction along the distance fromthe own vehicle to the object and an azimuth direction from the ownvehicle to the object, the image search region being a predeterminedrange defined based on, as a reference, the second position extending inthe direction along the distance and the azimuth direction; and thedetermination condition changing unit enlarges the image search regionin the direction along the distance such that the object determined tobe partially excluded from the acquired image is more easily determinedto be the same object in comparison with an object a part of which isdetermined not to be excluded in the acquired image.
 13. The vehiclecontrol apparatus according to claim 2, wherein the object determinationunit calculates i) based on a first position, an electromagnetic waveprediction time which is a predicted time until the object collides withthe own vehicle and ii) based on the second position, an imageprediction time which is a predicted time until the object collides withthe own vehicle; and sets, to the determination condition, a conditionthat the difference between the electromagnetic wave prediction time andthe image prediction time is equal to or less than the predeterminedthreshold; and the determination condition changing unit enlarges thepredetermined threshold such that the object determined to be partiallyexcluded from the acquired image is more easily determined to be thesame object in comparison with an object a part of which is determinednot to be excluded in the acquired image.
 14. The vehicle controlapparatus according to claim 2, further comprising a reliabilitycalculation unit for calculating a reliability of the same determinationof the objects, which is based on the first position and the secondposition, wherein the determination condition changing unit changes thedetermination condition on condition that the reliability is equal to orgreater than a predetermined value, such that the object determined tobe partially excluded from the acquired image is more easily determinedto be the same object in comparison with an object a part of which isdetermined not to be excluded in the acquired image.
 15. The vehiclecontrol apparatus according to claim 3, wherein the object determinationunit calculates i) based on a first position, an electromagnetic waveprediction time which is a predicted time until the object collides withthe own vehicle and ii) based on the second position, an imageprediction time which is a predicted time until the object collides withthe own vehicle; and sets, to the determination condition, a conditionthat the difference between the electromagnetic wave prediction time andthe image prediction time is equal to or less than the predeterminedthreshold; and the determination condition changing unit enlarges thepredetermined threshold such that the object determined to be partiallyexcluded from the acquired image is more easily determined to be thesame object in comparison with an object a part of which is determinednot to be excluded in the acquired image.
 16. The vehicle controlapparatus according to claim 3, further comprising a reliabilitycalculation unit for calculating a reliability of the same determinationof the objects, which is based on the first position and the secondposition, wherein the determination condition changing unit changes thedetermination condition on condition that the reliability is equal to orgreater than a predetermined value, such that the object determined tobe partially excluded from the acquired image is more easily determinedto be the same object in comparison with an object a part of which isdetermined not to be excluded in the acquired image.
 17. The vehiclecontrol apparatus according to claim 6, wherein the object determinationunit calculates an electromagnetic wave search region and an imagesearch region, and sets, to the determination condition, a conditionthat there is a region which overlaps on both the calculatedelectromagnetic wave search region and the calculated image searchregion, the electromagnetic wave search region being a predeterminedrange i) defined based on, as a reference, the first position and ii)extending in both a direction along the distance from the own vehicle tothe object and an azimuth direction from the own vehicle to the object,the image search region being a predetermined range defined based on, asa reference, the second position extending in the direction along thedistance and the azimuth direction; and the determination conditionchanging unit enlarges the image search region in the direction alongthe distance such that the object determined to be partially excludedfrom the acquired image is more easily determined to be the same objectin comparison with an object a part of which is determined not to beexcluded in the acquired image.